The semiconductor integrated circuit (IC) industry has experienced rapid growth in recent years. Technological advances in IC materials and design have produced various types of ICs that serve different purposes. One type of these ICs includes photonic devices, such as light-emitting diode (LED) devices. LED devices emit light through movement of electrons in a semiconductor material when a voltage is applied. LED devices have increasingly gained popularity due to favorable characteristics such as small device size, long life time, efficient energy consumption, and good durability and reliability.
A-lamps have been in use for over a century as the most commonly seen incandescent lamps. In the United States, a typical household has many A-lamps with the familiar bulb shape in use in overhead fixtures, table lamps, and the like.
Recent developments have led to a phasing out of incandescent lamps in some parts of the world. One candidate for replacing incandescent lamps is lamps based on Light-Emitting Diodes (LEDs). LEDs produce more light for the same amount of power compared to incandescent lamps.
There have been attempts at making LED-based A-lamps, but many are unsatisfactory. Traditionally, LED-based A-lamps produce forward lighting patterns because of the directive characteristics of LEDs. In some instances, forward light can be so bright that makes human eyes feel uncomfortable. Also, depending on how a luminaire of a directive A-lamp is installed, the A-lamp may radiate light in an undesirable or useless direction.
LEDs produce heat when radiating light. Thus, heat sinks are used for LED lighting luminaires in some conventional systems. It is typically easier to provide thermal management for a highly-directive luminaire that produces light from a single plane than it is to provide thermal management for a luminaire that attempts to approximate a uniform sphere of light. That is because some conventional LED A-lamps that attempt a spherical lighting pattern trap heat in the middle of the structure. Thus, in many designs, a desirable light pattern may be balanced with competing thermal management concerns. While some conventional LED lamps may be satisfactory in some aspects, LED lamps can use improvement.